Upholstery insulator pad and method of producing same



Jan. 6, 1970 w, so ETAL 7 3,487,481

UPHOLSTERY INSULATOR PAD AND METHOD OF PRODUCING SAME Filed NOV. 25, 1966 INVENTORJ. Mil/lam l: Ric/lama John 6. Herr BY la a E: 77cm;

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US. Cl. 5354 United States Patent 3,487,481 UPHOLS'IERY INSULATOR PAD AND METHOD OF PRODUCING SAME William F. Richardson, John G. Platt, and Lloyd E. Tieman, Carthage, Mo., assignors to Flex-O-Lators, Inc., Carthage, Mo., a corporation of Missouri Filed Nov. 25, 1966, Ser. No. 597,074 Int. Cl. A47c 23/32 5 Claims ABSTRACT OF THE DISCLOSURE An upholstery insulating pad including a series of closely Spaced, parallel spring wire cross strands, a

reinforcing spring wire extending transversely to said This invention relates to new and useful improvements in upholstery accessories, and has particular reference to that class of upholstery accessories commonly known as insulator pads.

An insulator pad consists of a spring wire or wirereinforced fabric sheet adapted to be inserted between the spring deck of a furniture or automotive seat structure and the padding layers applied over said spring deck, and primarily has the function of providing adequate support for said padding to prevent it from working down into the spaces between and within the spring units comprising the spring deck, said spring units often being Widely spaced apart and therefore offering only intermittent or interrupted support for the padding layers. A type of insulator pad in extremely wide and popular usage consists of a series of closely spaced apart parallel spring wires extending between and secured at their ends to relatively pliable side strands extending at right angles to said spring Wires. The spring wires may also be connected by relatively pliable intermediate strands extending parallel to said side strands, and also may be stitched through a sheet of burlap or the like forming an element of the pad.

However, a difficulty has arisen in connection with this type of insulator pad, due to the fact that while it is reasonably stiff and resistant to flexure about an axis at right angles to the parallel spring wires, it is relatively pliable and non-resistant to flexure about axes parallel to said spring wires. For various reasons discussed in copending application Ser. No. 542,940, filed Apr. 15, 1966 now patent No. 3,327,332, it is sometimes desirable that the pad have a substantial degree of resilient stiffness about axes parallel to the spring wires. Principally, these reasons are concerned with the provision of better padding support by the insulator pad over certain types of spring decks, notably the type of spring deck consisting of widely spaced apart, generally parallel serpentine or zig-zag springs affixed at their ends to the seating frame. It is often desirable to install the insulator pad with its spring wires parallel to such serpentine deck springs, but this would result in the fact that the pad wires disposed intermediate the deck springs would be very poorly supported due to the pliability of the side and intermediate strands of the pad, and could therefore support the overlying padding layers only very inadequately. It has therefore been proposed to incorporate relatively stiff spring wires into the pad extending transversely to the closely spaced parallel spring wires already discussed, whereby the pad will have resilient resistance to flexure about both axes. One method of doing so is disclosed in the above identified copending application. The present application contemplates a new and improved structure and method for adding said reinforcing Wires.

The basic problem is that of fastening spring wires securely together in right angled relationship, and it is not without difficulties. Welding or any process involving a high degree of heat is not practical, as it destroys the spring temper of the wires. Bending, crimping, knotting or other permanent deformation of the wires to form interlocking connections thereof also tends to impair the spring temper, as well as to work-harden the wires so that they become brittle and subject to breakage when the wire is later flexed, and further it greatly compli cates manufacturing methods and equipment, and increases the cost thereof. Nevertheless, the wires must be securely joined against relative movement.

Therefore, the principal object of the present invention is the provision of a structure and method for producing an upholstery insulator pad including a series of generally parallel spring wire cross strands and reinforcing spring wires extending transversely to said cross strands and secured thereto by means which, while providing a secure and permanent connection, do not involve heating, bending or other permanent deformation of the wires.

Generally, this object is accomplished by laying a reinforcing wire across said cross wires, extending a textile cord to pass under each of said cross wires and to pass over said reinforcing wire intermediate each adjacent pair of cross wires, and applying a liquid adhesive to join said reinforcing wire and its associated cord along the entire lengths thereof.

Other objects are simplicity and economy of construction, efficiency and dependability of operation, and adaptability for economical production in continuous lengths by automatic machinery.

With these objects in view, as well as other objects, which will appear in the course of the specification, refer.- ence will be had to the accompanying drawing, wherein:

FIG. 1 is a plan view of an upholstery insulator pad embodying the structure and production method contemplated by the present invention,

FIG. 2 is an enlarged, fragmentary view similar to FIG. 1 showing a length of one of the reinforcing wires and portions of the cross wires associated therewith, with the securing adhesive omitted for clarity,

FIG. 3 is a sectional view taken on line IIIIII of FIG. 2, with the adhesive included, and

FIG. 4 is a view similar to FIG. 3, but with the adhesive omitted.

Like reference numerals apply to similar parts throughout the several views, and the numeral 2 applies generally to an upholstery insulator pad the construction and pro duction methods of which embody the present invention. As shown, it includes a pair of parallel side strands 4 which may be formed of a relatively pliable material such as twisted kraft paper, and a series of closely spaced apart parallel cross strands 6 constituting spring wires each having its extreme ends secured respectively to side strands 4, as by being twisted clampingly thereabout. Said cross wires perform the primary pad function of supporting padding layers over the spring deck of a seating structure, and the spacing therebetween will therefore be determined by the nature of the padding material to be supported. A spacing of about one inch between wires has been found satisfactory in most instances.

It will be seen that the pad as thus far described has good resilient resistance to flexure about any axis transverse to cross Wires 6, but little if any such resistance to flexure about any axis parallel to said cross wires.

This lack is undesirable when applying the pad over certain types of spring decks, for the reason discussed above. Moreover, the fault could not be corrected by making side strands 4 stiffer, as for example by providing them with spring wire cores, since said side strands are not disposed in the principal load area of the pad where the greatest flexure thereof normally occurs in usage.

Therefore, to impart to the pad the desired resilient resistance to flexure about axes parallel to cross wires 6, a plurality of reinforcing strands 8 are extended across the pad at right angles to cross wires 6 and at evenly spaced intervals between side strands 4, and are firmly connected to said crosswires. These reinforcing stands are detailed in FIGS. 2, 3, and 4. Each reinforcing strand includes a spring wire 10, a pliable cord 12 of textile fiber'or the like, and an adhesive coating 14. First, wire 10 is laid across wires 4, so as to be disposed at the same side of all of wires 4, in this case the top side. Then cord 12 is extended along wire 10 so as to pass under each wire 4, and to pass over wire 10 intermediate each successive pair of wires 4, whereby to secure the wires in assembly. Then, while maintaining cord 12 taut under considerable tension, adhesive 14 is applied in liquid form to the entire length of wire 10 and its associated cord 12, the cord preferably being maintained taut until the adhesive has set. The pad is then complete and ready for use. The amount of adhesive used is not particularly critical, and while it is shown as forming a complete and unbroken coating over Wire 10 and cord 12, it is sufficient for some purposes if enough adhesive is used to form a good bond between the wire and cord, and with wires 6 at their intersection therewith. This holds the wires and cords firmly and permanently in assembly, preventing separation of wires 6 from wire 10, and also preventing even slight transverse slippage of wires 6 longitudinally along wire 10. The latter movement could not be prevented entirely by the cord alone without the adhesive, and its prevention is important in eliminating the grinding or rubbing noises which might otherwise occur due to relative movement between the contacting wires as the pad is flexed in usage.

For other considerations it is desirable that sufficient adhesive be applied to thoroughly impregnate the fibers of cord 12 while still in its liquid state. The penetration of the cord by the liquid adhesive may be and preferably is promoted and encouraged by rolling each wire 10 and its associated cord between a pair of soft faced pressure rollers just after the adhesive has been applied, in order to force the adhesive into the cord. This penetration has two important functional advantages. First, when the cord is so impregnated, the contraction of the adhesive as it sets tends to contract or shorten the cord, thereby drawing it still tighter to increase the tightness of the connection between the wires provided thereby. Second, once the adhesive has set, it provide a matrix binding the fibers of the cord so as to inhibit stretching of the cord in use, thereby preserving the security of the connection over longer periods of usage. This prevention of stretching is further improved by the pre-stressing of the cord as the adhesive is applied and allowed to set. The cord of course supplies the tensile strength necessary for a good connection, the adhesive alone not having good tensile strength, but the adhesive can and does increase the tensile strength of the cord as described. The adhesive itself should be of a type which is flexible when set, so as not to crack or shatter when flexed during usage of the pad.

The pad and method shown and described are also well adapted for production and use on the automatic machinery on which the basic pad, without reinforcing strands 8, are commonly produced. In such machines, side strands 4 are advanced longitudinally past a work station in steps corresponding in length to the spacing between wires 6. At each pause, a wire 6 is inserted transversely to the side strands, cut to the desired length, and its ends twisted about said side strands. The pad is thereby produced in continuous lengths, from which the length necessary for each particular job may be cut by severing side strands 4. It will be readily apparent that in such a machine, it would be reasonably simple to introduce therein wires 10 and cords 12 from continuous spools and to advance them in steps concurrently with the side strands, and directing each cord 12 beneath each wire 6 as said wire is inserted, and over wire 10 intermediate the insertion of successive wires 6. The adhesive 14 could then be applied, and the wire 10-cord 12 combination passed between pressure rollers disposed above and below the pad, after the completed pad leaves the work station at which wires 6 are inserted. The completed pad may still be produced and sold in continuous lengths, and may still be cut into any desired lengths as required by cutting the side strands and reinforcing strands between any successive pair of wires 6. Cutting the reinforcing strands cannot cause loosening or disengagement of cords 12, due to the presence of the adhesive.

The number of reinforcing strands 8 incorporated in a pad of a given width is of course subject to change as may be deemed advisable. The reinforcing strands are not necessary to the primary pad function of providing a reasonably continuous deck for supporting the overlying padding layers, this function being fulfilled by the closeness of wires 6 themselves. For this reason, it is therefore generally preferable from an economic standpoint to use as few reinforcing strands 8 as possible which will nevertheless provide the desired degree of resilient resistance of the pad to flexure about axes parallel to wires 6. This resistance may of course be increased by using a larger number of reinforcing strands, but substantially the same effect can be obtained with fewer reinforcing strands by making wires 10 substantially heavier, and hence stiffer, than Wires 6, as illustrated.

What we claim as new and desire to protect by Letters Patent is:

1. In an upholstery insulating pad including a series of parallel, closely spaced spring wire cross strands defining a plane, the combination of:

(a) a linear reinforcing spring wire extending transversely to said cross wires in intersecting relationship thereto, entirely at one side of the plane defined by i said cross strands,

(b) a pliable cord extending along said reinforcing wire, said cord being trained about said reinforcing wire intermediate each successive pair of said cross wires, and around each of said cross wires at the side thereof distal from said reinforcing wire, and

(c) a flexible adhesive binding said cord and said reinforcing wire together along substantially their entire length, and to each of said cross wires.

2. The method of producing an upholstery pad including a series of generally parallel, closely spaced apart spring wire cross strands and a linear reinforcing spring wire reinforcing strand extending transversely to said cross wires and attached thereto, said method comprising the successive steps of:

(a) laying said reinforcing spring wire across said cross wires,

(b) extending a pliable cord along said reinforcing spring wire and wrapping it about said reinforcing wire and cross wires to secure them together, training said cord about the side of each of said cross wires distal from said reinforcing wire, and about the side of said reinforcing wire distal from said cross wires, intermediate each successive pair of said cross wires,

(c) applying a liquid adhesive to secure said reinforcing wire and cord together and to said cross wires, and

(d) allowing said adhesive to set.

3. The method as recited in claim 4 with the additional step of:

(a) applying a longitudinal tension to said cord as said 5 6 adhesive is applied, and maintaining said tension as force said adhesive into the fibers of said cord to said adhesive sets. form a binding matrix therefor. 4. The method as recited in claim 4 wherein said pliable cord is formed of a fibrous material, and with the ad- References Clfed difionalstep 5 UNITED STATES PATENTS (a) applying pressure to said cord after said adhesive has been applied but before it has set, whereby to 3327332 6/1967 Richardson et 297456 X force said adhesive into the fibers of said cord to form $E 1l :1 etgl 5% a binding matrix therefor. i

5. The method as recited in claim 4 wherein said pliable 10 i g 1-52 16 ord is formed of fibrous material, and wit the addii m rt tional steps of:

(a) applying a longitudinal tension to said cord as said ROBERT E Examiner adhesive is applied, and maintaining said tension as LITMAN, Asslstant EXamlIler said adhesive sets, and 1 U S C1 X R (b) applying pressure to said cord after said adhesive has been applied but before it has set, whereby to 156l6l; 16189; 297455 

